Inter- and intrafractional movement of the tumour in extracranial stereotactic radiotherapy of NSCLC

Figures & data

Table I.  Patient specifics.

Age
Median (min; max)	74	(48; 86)
Gender
Female	13	(59%)
Male	9	(41%)
Performance (WHO)
0	6	(27%)
1	8	(36%)
2	8	(36%)
Smoking history
Current smoker	17	(77%)
Former smoker	5	(23%)
FEV1 (l/min)
Median (min; max)	0.96	(0.56; 2.45)
Tumour size (cm^3)
Median (min; max)	12	(1; 105)
Stage
T1N0	12	(55%)
T2N0	10	(45%)
Affected side of lung
Right	13	(59%)
Left	8	(36%)
Both	1	(5%)
Tumour location
Craniel for carina	10	(45%)
Caudal for carina	12	(55%)
Tumour location relative to apex
Median (min; max)	0.40	(0.13; 0.81)
Chest wall adherent
Yes	9	(41%)
No	13	(59%)
Histology
Squamous cell carcinoma	8	(36%)
Adenocarcinoma	12	(55%)
Undifferentiated	2	(9%)

Figure 1.  Patient immobilization using Lax-Blomgreen stereotactic body frame.

Table II.  Standard deviations of the tumour movements (mm).

	Left-Right	Anterior-Posterior	Cranio-Caudal
Intra-fractional	0.9±0.1	1.6±0.2	2.0±0.2
Inter-fractional	1.1±0.1	1.3±0.1	1.7±0.2
Accuracy in SBF	1.5±0.2	1.1±0.2	1.7±0.3
Sum of Inter and SBF	1.8±0.1	1.7±0.2	2.4±0.3
Sum of Inter, Intra and SBF	2.0±0.2	2.3±0.2	3.1±0.3

Table III.  Charcteristics of the peak-to-peak intra-fractional movement (mm).

	Left-Right	Anterior-Posterior	Cranio-Caudal
Minimum	1	2	2
Maximum	6	14	23
Mean	4	6	8
Median	4	5	6

Figure 2.  Standard deviation of the intrafractional movement in the Cranio-Caudal direction as function of the tumour position in the Cranio-Caudal direction. The Pearson correlation coefficient is 0.74. The fit is a linear regression. The uncertainty on the slope coefficient and on the constant is 0.085 and 0.041 (1SD), respectively.